The present invention relates to semiconductor integrated circuit devices. More particularly, it relates to techniques which are effective when applied to a semiconductor integrated circuit device for use in a color VTR (Video Tape Recorder).
Color VTRs which are currently on the market, are furnished with the record (REC) function of recording a color picture and the playback (PB) function of playing back the recorded color picture.
The record of the color picture proceeds as follows: First, a color video signal generated through a receiving antenna as well as a tuner is isolated into a luminance signal (hereinbelow, also termed "Y signal") and a color signal (hereinbelow, also termed "C signal"). The isolated luminance signal is subjected to FM (frequency modulation), while the isolated color signal is subjected to frequency conversion. The frequency-modulated luminance signal and the frequency-converted color signal are mixed with each other, whereupon the resulting signal is recorded on a video tape through a video head.
The playback of the color picture proceeds as follows: First, the color picture recorded on the video tape is read out by a video head and is isolated into a luminance signal and a color signal. The isolated luminance signal is subjected to frequency demodulation, while the isolated color signal is subjected to frequency conversion. The frequency-demodulated luminance signal and the frequency-converted color signal are synthesized with each other into a color video signal. This color video signal is applied to a TV monitor so as to play back the color picture.
In order to reduce the size thereof, the color VTR stated above has an FM-modulator circuit, an FM-demodulator circuit and frequency converter circuits implemented in the form of ICs (semiconductor integrated circuit devices). The FM-modulator circuit and FM-demodulator circuit, and the frequency converter circuits deal with operating frequency bands different from each other, so that they are individually put into the ICs in order to reduce the degradation of a picture quality attributed to a crosstalk oscillation phenomenon. That is, the FM-modulator circuit of a record circuit and the FM-demodulator circuit of a playback circuit (luminance signal processing circuits) are constructed of one IC, while the frequency converter circuits of the record and playback circuits (color signal processing circuits) are constructed of the other IC.
By the way, the built-in ICs of the color VTRs are explained in, for example, "Nikkei Electronics" issued by Nikkei McGraw-Hill Inc., dated Sep. 5, 1988 (No. 455), pp. 179-183.